Search results for "Electron diffraction"

On the possibility of synthesizing multilayered coatings in the (Ti,Al)N system by RGPP: A microstructural study

2019

International audience; Radiofrequency magnetron sputtering combined with reactive gas pulsing process was used to synthesize two titanium aluminum nitride multilayer films using a periodically controlled nitrogen flow rate changing from 0.4 to 1 sccm (sample S04-1) and from 0 to 1 sccm (sample S0-1). A metallic TiAl buffer layer was deposited on the etched substrates before the deposition to enhance their adhesion. The films were characterized using mainly transmission electron microscopy and electron diffraction. The role of the crystallinity of the buffer TiAl metallic layer deposited before gas introduction on the growth orientations is emphasized. It is shown that the formation of a mu…

Electron diffraction tomography and X-ray powder diffraction on photoredox catalyst PDI

2019

N,N-Bis(2,6-diisopropylphenyl)-perylene-3,4,9,10-bis(dicarboximide) (PDI-iPr) is starting to be widely used as a metal-free homogeneous photoredox catalyst. The crystal structure was determined by a combination of electron diffraction tomography and X-ray powder diffraction and further validated by DFT-D calculations. Surprisingly, the molecular geometry of PDI-iPr leads to voids in the packing.

Epitaxial thin films of intermetallic compounds

2002

Publisher Summary The potential of epitaxial thin films of intermetallic compounds in basic and applied research is emerging. Although the growth of semiconductor heterostructures and compounds based on molecular beam epitaxy (MBE) and related methods has come through a 30-year history of ongoing refinement and sophistication, still much has to be learned concerning the growth and characterization of even moderately complex metallic thin film structures. MBE represents a well-defined crystallization technique based on the reactions among molecular or atomic beams of the constituent elements on a substrate or template at elevated temperatures in an ultrahigh vacuum (UHV) environment. Owing t…

An epitaxial hexagonal tungsten bronze as precursor for WO3 nanorods on mica.

2008

International audience; Tungsten oxide nanorods are grown at atmospheric pressure and low temperature (360 1C), by sublimation of WO3 and condensation on mica substrates. The nanorods are characterized by atomic force microscopy, high-resolution electron microscopy, energy-dispersive X-ray spectroscopy and high energy electron diffraction. The experimental results evidence the formation of a hexagonal tungsten bronze at the nanorod–substrate interface. The epitaxial relationships of the nanorods on mica are determined and the role of epitaxial orientation of the interfacial bronze in the nanorod growth and morphology are discussed.

ECS-3: A Crystalline Hybrid Organic-Inorganic Aluminosilicate with Open Porosity

2011

Detecting Crystalline Nonequilibrium Phases on the Nanometer Scale

2012

The use of Automated electron Diffraction Tomography (ADT) is presented as a novel approach for crystallization studies at the nanometer scale for nonequilibrium phases. Here, ADT was applied to elucidate the structural identity of the recently reported hexagonal morphology of caffeine crystals, which grow only on specific surfaces. Caffeine was crystallized from solution on a specially treated TEM carbon grid. The analysis of ADT data revealed that the lattice parameters of these hexagons match those of the high temperature α- form of caffeine. Furthermore, it was observed that in this hexagonal morphology, the α-form remained stable for a prolonged period of time. The stabilization of hex…

Initial stages of self-assembled InAs/InP(001) quantum wire formation

2007

4 páginas, 2 figuras.-- PACS codes: 78.67.Lt; 68.65.La; 68.37.Ps.-- Comunicación oral presentada a la 14ª International Conference on Molecular Beam Epitaxy - MBE XIV celebrada en Tokio (Japón) del 3 al 8 de Septiembre de 2006.

Transmission electron microscopy investigation of oxidation of (110)NiAl single crystal with wedge-shaped profile

2016

Abstract Low energy electron diffraction (LEED), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX), and electron energy loss spectroscopy (EELS) investigations of oxidation processes in (110)NiAl single crystal of wedge like shape, i.e., on the sample’s areas of different thickness, were carried out. It was found that in the result of several cycles of ion etching, annealing and oxidation the upper layer of (110)NiAl is enriched with Ni. With the increase of Ni concentration from 50 to 100 at. %, the stoichiometry of the near surface area changes and the new phases of Ni3Al and Ni with Al doping are formed one after another. Up to Ni content of 75 at. %…

On the metal distribution in the system GeTe−Sb2Te3

1988

The structures of GeSb2Te4, Ge2Sb2Te5 and GeSb4Te7 are not determined completely by means of classical X-ray or electron diffraction studies. We have measured the Mossbauer parameters of121Sb in these compounds as well as in their binary constituent Sb2Te3 as an attempt to improve our knowledge on the question.

Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter

2021

Journal of synchrotron radiation 28(6), 1891 - 1908 (2021). doi:10.1107/S1600577521010511